1. Field of the Invention
This invention pertains to a method of making a paper bag construction of food-grade quality.
2. Prior Art
U.S. Pat. No. 3,973,045 discloses a popcorn package for microwave popping. The assignee of the present invention is a manufacturer and supplier of bags to be filled with unpopped popcorn and shortening, and the firm that does such filling closes the mouth of the bag. When the package is placed in a microwave oven and heated, the popcorn pops and causes the bag to inflate and to develop an internal pressure. If that pressure should cause the originally closed end of the bag to leak, then melted shortening or oil can escape, and the hot gas within the package can also escape, thereby preventing some of the unpopped kernels from popping, and also spoiling the interior of the oven.